Liquid crystal modes may be classified into a monostable mode and bistable mode according to a state of stability. The monostable mode continuously requires external energy supply in order to maintain at least any one of the states of liquid crystal and the bistable mode requires external energy only when the state changes.
Patent Document 1 (U.S. Patent Publication No. 2006-0091538) discloses a bistable liquid crystal cell capable of being switched between a haze mode and a non-haze mode. The liquid crystal cell disclosed in Patent Document 1 uses a liquid crystal compound, and an ionic compound capable of inducing so-called electrohydrodynamic instability (EHDI), and can be switched between a haze mode and a non-haze mode by variable frequency. However, this type of liquid crystal cell requires very high driving voltage for being switched between a haze mode and a non-haze mode, and thus there is a practical limit in applying it to various display units. For this reason, recently, research on bistable liquid crystal cells capable of being switched between a haze mode and a non-haze mode, while having an excellent haze characteristic even with low driving voltage has been increasing in the field of display units.